1. Field of the Disclosure
The present disclosure relates generally to authentication of printer supply items and more particularly to updating a revocation list using an Internet name server.
2. Description of the Related Art
Printers use consumables such as toner cartridges, fusers, etc. These consumables are often counterfeited and sold to unsuspecting consumers. Counterfeit supplies do not conform to the printer manufacturer's requirements and may damage the customer's printers. To deter counterfeiters, printer manufacturers incorporate authentication modules into the consumables. Printers verify the authenticity of consumables by communicating with the authentication modules. Thus, to counterfeit a consumable a counterfeiter must also counterfeit the associated authentication module. Authentication modules contain, for example, authentication ASICs that are difficult to counterfeit.
However, a determined counterfeiter may duplicate authentication ASICs. The duplicates may be identical and thus have the same internal serial number. Printers may be fooled by the duplicated authentication ASICs enabling counterfeiters to sell counterfeit printer supply items. Eventually, the printer manufacturer discovers the counterfeit printer supply items, analyzes the duplicated authentication ASICs, and adds the duplicated serial number to a revocation list of revoked serial numbers. This revocation list is used by printers to detect duplicated authentication ASICs and to alert users that their printer supply item is a counterfeit. Of course, the counterfeiters are free to duplicate another authentication ASIC which will work in the printers until the new serial number is also added to the revocation list. Thus, it is crucial to quickly update the printer's revocation list as new duplicated authentication ASIC serial numbers are discovered to minimize the number of counterfeit consumables.
The revocation list may be updated by updating the printer firmware. This is difficult to do in the field because firmware files are large and sending firmware updates places a burden on customer networks. Also, many customers have network firewalls that prevent a printer from connecting to an update server located outside the firewall using network file transfer protocols such as FTP. Thus, once a printer is installed it may never receive updated firmware. An updated revocation list may be written to a printer supply item's authentication module during manufacturing and the updated revocation list may be transferred to a printer when the printer supply item is installed into the printer. In this way, the printer's revocation list may be updated while the printer is in the field. However, it may take many months for an updated revocation list to be seen by all printers in the field since existing inventory of older consumables must be used up before the newer consumables make it to the printers. During that delay, many counterfeit consumables may reach the market. Also, if a printer is only given counterfeit supplies it will never receive an updated revocation list. What is needed is a method to more quickly update revocation lists of printers in the field that works through firewalls.